Introduction to the Arthropoda

. . . the REAL rulers of the Earth. . .

By nearly any measure, the most successful
animals
on the planet are the arthropods.
They have conquered land, sea and air, and make up
over three-fourths of all currently known living and
fossil organisms, or over one
million species in all. Since many arthropod species remain
undocumented or undiscovered, especially in tropical
rain forests, the true number of
living arthropod species is probably in the tens of millions.
One recent conservative estimate puts the number of arthropod species
in tropical forests at 6 to 9 million species (Thomas, 1990).

Arthropods range in distribution from the deep sea to mountain peaks,
in size from the
king crab with its 12-foot armspan to microscopic
insects and
crustaceans, and in taste from chocolate covered ants to crawfish
jambalaya and lobster Newburg. Despite this unbelievable diversity,
the basic body plan of arthropods is fairly constant. Arthropods
have a stiff cuticle made largely of chitin and proteins, forming
an exoskeleton that may or may not be further stiffened with
calcium carbonate. They have segmented bodies and show various patterns
of segment fusion (tagmosis) to form integrated units (heads, abdomens,
and so on). The phylum takes its name from its distinctive jointed
appendages, which may be modified in a number of ways to
form antennae, mouthparts, and reproductive organs.

Click on the buttons below to learn more about the Arthropoda.

You can navigate deeper into the arthropod groups by selecting Systematics!